scholarly journals Interactions of the α3β2 Nicotinic Acetylcholine Receptor Interfaces with α-Conotoxin LsIA and its Carboxylated C-terminus Analogue: Molecular Dynamics Simulations

Marine Drugs ◽  
2020 ◽  
Vol 18 (7) ◽  
pp. 349
Author(s):  
Jierong Wen ◽  
David J. Adams ◽  
Andrew Hung
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Neurological Diseases ◽  
Nicotinic Acetylcholine ◽  
Binding Interface ◽  
C Terminus ◽  
Dynamics Simulations ◽  
The Individual ◽  
Carboxy Terminal ◽  
Subtype Selective

Notably, α-conotoxins with carboxy-terminal (C-terminal) amidation are inhibitors of the pentameric nicotinic acetylcholine receptors (nAChRs), which are therapeutic targets for neurological diseases and disorders. The (α3)2(β2)3 nAChR subunit arrangement comprises a pair of α3(+)β2(−) and β2(+)α3(−) interfaces, and a β2(+)β2(−) interface. The β2(+)β2(−) interface has been suggested to have higher agonist affinity relative to the α3(+)β2(−) and β2(+)α3(−) interfaces. Nevertheless, the interactions formed by these subunit interfaces with α-conotoxins are not well understood. Therefore, in order to address this, we modelled the interactions between α-conotoxin LsIA and the α3β2 subtype. The results suggest that the C-terminal carboxylation of LsIA predominantly influenced the enhanced contacts of the conotoxin via residues P7, P14 and C17 on LsIA at the α3(+)β2(−) and β2(+)α3(−) interfaces. However, this enhancement is subtle at the β2(+)β2(−) site, which can compensate the augmented interactions by LsIA at α3(+)β2(−) and β2(+)α3(−) binding sites. Therefore, the divergent interactions at the individual binding interface may account for the minor changes in binding affinity to α3β2 subtype by C-terminal carboxylation of LsIA versus its wild type, as shown in previous experimental results. Overall, these findings may facilitate the development of new drug leads or subtype-selective probes.

Pathologic role of neuronal nicotinic acetylcholine receptors in epileptic disorders: implication for pharmacological interventions

2015 ◽  
Vol 26 (2) ◽  
Author(s):  
Mehdi Ghasemi ◽  
Arash Hadipour-Niktarash
Keyword(s):  
Animal Models ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Neurological Diseases ◽  
Juvenile Myoclonic Epilepsy ◽  
Neuronal Nicotinic Acetylcholine Receptors ◽  
Pharmacological Interventions ◽  
Nicotinic Acetylcholine ◽  
Neuronal Nachr

AbstractAccumulating evidence suggests that neuronal nicotinic acetylcholine receptors (nAChRs) may play a key role in the pathophysiology of some neurological diseases such as epilepsy. Based on genetic studies in patients with epileptic disorders worldwide and animal models of seizure, it has been demonstrated that nAChR activity is altered in some specific types of epilepsy, including autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) and juvenile myoclonic epilepsy (JME). Neuronal nAChR antagonists also have antiepileptic effects in pre-clinical studies. There is some evidence that conventional antiepileptic drugs may affect neuronal nAChR function. In this review, we re-examine the evidence for the involvement of nAChRs in the pathophysiology of some epileptic disorders, especially ADNFLE and JME, and provide an overview of nAChR antagonists that have been evaluated in animal models of seizure.

5-Iodo-A-85380, an α4β2 Subtype-Selective Ligand for Nicotinic Acetylcholine Receptors

2000 ◽  
Vol 57 (3) ◽  
pp. 642-649 ◽  
Author(s):  
Alexey G. Mukhin ◽  
Daniela Gündisch ◽  
Andrew G. Horti ◽  
Andrei O. Koren ◽  
Gilles Tamagnan ◽  
...  
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Nicotinic Acetylcholine ◽  
Selective Ligand ◽  
Subtype Selective

scholarly journals High-Throughput Patch Clamp Screening in Human α6-Containing Nicotinic Acetylcholine Receptors

2017 ◽  
Vol 22 (6) ◽  
pp. 686-695 ◽  
Author(s):  
Lucas C. Armstrong ◽  
Glenn E. Kirsch ◽  
Nikolai B. Fedorov ◽  
Caiyun Wu ◽  
Yuri A. Kuryshev ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Cell Line ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Brain Regions ◽  
Tobacco Product ◽  
Tobacco Products ◽  
Nicotinic Acetylcholine ◽  
Automated Patch Clamp ◽  
Subtype Selective

Nicotine, the addictive component of tobacco products, is an agonist at nicotinic acetylcholine receptors (nAChRs) in the brain. The subtypes of nAChR are defined by their α- and β-subunit composition. The α6β2β3 nAChR subtype is expressed in terminals of dopaminergic neurons that project to the nucleus accumbens and striatum and modulate dopamine release in brain regions involved in nicotine addiction. Although subtype-dependent selectivity of nicotine is well documented, subtype-selective profiles of other tobacco product constituents are largely unknown and could be essential for understanding the addiction-related neurological effects of tobacco products. We describe the development and validation of a recombinant cell line expressing human α6/3β2β3V273S nAChR for screening and profiling assays in an automated patch clamp platform (IonWorks Barracuda). The cell line was pharmacologically characterized by subtype-selective and nonselective reference agonists, pore blockers, and competitive antagonists. Agonist and antagonist effects detected by the automated patch clamp approach were comparable to those obtained by conventional electrophysiological assays. A pilot screen of a library of Food and Drug Administration–approved drugs identified compounds, previously not known to modulate nAChRs, which selectively inhibited the α6/3β2β3V273S subtype. These assays provide new tools for screening and subtype-selective profiling of compounds that act at α6β2β3 nicotinic receptors.

scholarly journals Effects of C-Terminal Carboxylation on α-Conotoxin LsIA Interactions with Human α7 Nicotinic Acetylcholine Receptor: Molecular Simulation Studies

Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 206 ◽  
Author(s):  
Jierong Wen ◽  
Andrew Hung
Keyword(s):  
Conformational Changes ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Salt Bridge ◽  
Md Simulations ◽  
Α7 Nicotinic Acetylcholine Receptor ◽  
Nicotinic Acetylcholine ◽  
Α7 Nachr ◽  
C Terminus ◽  
Toxin Receptor

α-Conotoxins selectively bind to nicotinic acetylcholine receptors (nAChRs), which are therapeutic targets due to their important role in signaling transmission in excitable cells. A previous experimental study has demonstrated that carboxylation of the C-terminal of α-conotoxin LsIA reduces its potency to inhibit human α7 nAChR relative to naturally amidated LsIA. However, little is known about the contribution of conformational changes in the receptor and interactions, induced by C-terminal amidation/carboxylation of conotoxins, to selective binding to nAChRs, since most conotoxins and some disulfide-rich peptides from other conotoxin subfamilies possess a naturally amidated C-terminal. In this study, we employ homology modeling and molecular dynamics (MD) simulations to propose the determinants for differential interactions between amidated and carboxylated LsIAs with α7 nAChR. Our findings indicate an overall increased number of contacts favored by binding of amidated LsIA versus its carboxylated counterpart. Toxin-receptor pairwise interactions, which may play a role in enhancing the potency of the former, include ARG10-TRP77, LEU141 and CYS17-GLN79 via persistent hydrogen bonds and cation-π interactions, which are weakened in the carboxylated form due to a strong intramolecular salt-bridge formed by ARG10 and carboxylated C-terminus. The binding of amidated LsIA also induces enhanced movements in loop C and the juxtamembrane Cys-loop that are closely associated with receptor function. Additionally, the impacts of binding of LsIA on the overall structure and inter-subunit contacts were examined using inter-residue network analysis, suggesting a clockwise tilting of the α7 C and F loops upon binding to carboxylated LsIA, which is absent for amidated LsIA binding. The predicted molecular mechanism of LsIA binding to the α7 receptor may provide new insights into the important role of the C-terminal in the binding potency of conotoxins at neuronal nAChRs for pharmacological purposes.

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